The eccentric umbrella in the prior art disclosed in the patent CN200720122950.7 comprises a shaft, a framework and a canopy, in which the shaft passes though a runner, one end of a rib forming the framework is hinged on an upper ring. One end of a stretcher is hinged on the rib and the other end is hinged on a lower ring. The ribs and stretchers are distributed in 360°. The canopy is fixed on the framework and a ferrule. Between the shaft and the runner is cooperatively disposed with springs to guide the umbrella or lock the opened umbrella. A top notch is fixed on the top of the shaft. One side of the main frame formed by crossed straight braces is respectively hinged with the upper and the lower rings and the other side is respectively hinged with the top notch and the runner. An auxiliary brace forming an auxiliary frame is hinged with the top notch, the runner and the ferrule. The eccentric umbrella disclosed in the patent CN200720122950.7 has structure and reliability problems. In addition, it also has poor anti-wind property, and thus it is necessary to make an improvement.